function isItemOnly(str){
    const arr=JSON.parse(str)
    const r=[]
    for (let i = 0; i < arr.length; i++) {
        if(arr.indexOf(arr[i])===arr.lastIndexOf(arr[i])){
            r.push(arr[i])
        }
    }
    if(r!=null){
        console.log(true)
        return true
    }
}
var ss=read_line()
isItemOnly(ss)